1. Field of the Invention
This application is directed to methods and apparatuses for mechanically coupling a disk drive actuator body and a rotary bearing cartridge of a head stack assembly.
2. Description of the Related Art
Considerable markets exist for hard disk drives for mass-market host computer systems such as servers, desktop computers, and laptop computers. To be competitive in these markets, a hard disk drive must be relatively inexpensive, and must accordingly embody a design that is adapted for low-cost mass production. Low-cost mass production is facilitated by designs that can be easily assembled and re-worked if necessary. In addition, the drive must provide substantial capacity, rapid access to data, and reliable performance.
Satisfying competing constraints of low-cost, small size, high capacity, and rapid access requires innovation in each of numerous components and methods of assembly including methods of assembly of various components into certain subassemblies. A head disk assembly and a printed circuit board assembly are typical subassemblies of a hard disk drive. The head disk assembly includes an enclosure including a base and a cover, at least one disk having at least one recording surface, a spindle motor for causing each disk to rotate, and an actuator arrangement.
One conventional actuator arrangement is a rotary actuator, which consists of an arm that extends a head over the disk. The arm is pivoted about an axis by a pivot bearing assembly. Conventional pivot assemblies-to-actuator arm connections include press-fit engagement, coupling with set screws and other conventional fasteners. In some cases, an adhesive is located in the interface between the pivot bearing assembly and the actuator arm.
The foregoing techniques for interconnecting an actuator arm with a pivot bearing assembly may have significant drawbacks. For example, adhesives can emit gas into the enclosure, which can result in residue on the disk and damage to the heads, the disks, or the head-disk interface. Press-fit engagement involves application of a force between the pivot assembly and the actuator that can vary across the distribution of these components and can be excessive in some cases. In some cases, the force of the press-fit can result in scoring of the actuator bore and generation of particles within the enclosure. Fasteners such as set screws also can produce undesirable strain or particle generation, which can damage to the heads and the disks.